Ink-jet printing has become a popular way of recording images on various media surfaces, particularly paper, for a number of reasons, including, low printer noise, capability of high-speed recording, and multi-color recording. Additionally, these advantages of ink-jet printing can be obtained at a relatively low price to consumers. Though there has been great improvement in ink-jet printing, improvements are followed by increased demands from consumers for higher speeds, higher resolution, full color image formation, increased stability, etc.
As new ink-jet inks and print engines are developed, several traditional characteristics are considered when evaluating the ink in conjunction with a printing surface or substrate. Such characteristics include edge acuity and optical density of the image on the surface, gloss, black to color bleed control, dry time of the ink on the substrate, adhesion to the substrate, lack of deviation in ink droplet placement, presence of all dots, resistance of the ink after drying to water and other solvents, long term storage stability, and long term reliability without pen material degradation or nozzle clogging. The long term reliability without material degradation or nozzle clogging becomes even more important with the advent of print engines that eject smaller drop volumes. Though the above list of characteristics provides an illustration of factors to be optimized for improved ink-jet printing, there are challenges associated with satisfying all of the above characteristics. Often, the inclusion of an ink component meant to satisfy one of the above characteristics can prevent another characteristic from being met. Thus, traditional commercial inks for use in ink-jet printers represent a compromise in an attempt to achieve at least an adequate response in meeting all of the above listed characteristics.
Typically dry time performance of an inkjet ink has been controlled with low molecular weight ink additives such as surfactants, penetrants, or volatile ink vehicle components. Other solutions include reducing pigment load or ink flux. However, many of these techniques often result in low optical density (OD) on printed media, poor print quality such as edge acuity, mottle, and/or complicated print mode design.